Prime Time Replay:
Physicist Lee Smolin
on his book The Life of the Cosmos
MsgId: *infinities(1)
Date: Sun Jul 27 21:00:31 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Good evening and welcome to another edition of Infinities. I'm your host, Rob Killheffer, senior editor of Omni Internet, and with me tonight is Penn State theoretical physicist Lee Smolin. Dr. Smolin has recently published a fascinating book, "THE LIFE OF THE COSMOS," which argues for a revolutionary reimagining of some of our basic assumptions about the development of the cosmos and the laws which govern its functions. Welcome, Lee!
MsgId: *infinities(2)
Date: Sun Jul 27 21:03:14 EDT 1997
From: Lee_Smolin At: 128.118.49.137
HI, nice to be here, its the first time I do something like this.
MsgId: *infinities(3)
Date: Sun Jul 27 21:05:54 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Later in the hour I'll open the room for questions, but to start let's plunge into the ideas in "THE LIFE OF THE COSMOS." One of the assertions at the heart of the book is that we need to give up the notion of the basic particles and forces of the universe as absolute, unchanging entities, and conceive of them instead as "contingent," the product of the evolutionary history of the universe they compose. That's a challenging proposal. Perhaps you can summarize the reasons why you think it's not only possible but necessary to think of the cosmos this way?
MsgId: *infinities(5)
Date: Sun Jul 27 21:15:05 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Hi, my last message sat there for a while, then there was a messgae telling me there is an error. I hope this gets to you...
MsgId: *infinities(6)
Date: Sun Jul 27 21:16:57 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Look at my last message, Lee. If you've got a long message, you'll need to send it in parts -- type two or three sentences, add a "cont" or a "..." at the end, send it, then begin again.
MsgId: *infinities(7)
Date: Sun Jul 27 21:17:13 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Hi, this is a bit amusing, anyway, as I was saying, there are two reasons to believe that the laws of nature we observe at scales we can probe experimentally must have been chosen by some historical process. The first reason is that at present our best knowledge about fundamental physics leads us with a picture in which the basic laws (which should come from some version of quantum gravity and string theory) manifest themselves in many different "phases" in which the laws are different.
MsgId: *infinities(9)
Date: Sun Jul 27 21:21:04 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
When and where might the physical laws be different? That is, would this just be in the distant past, shortly after the "big bang," or would we find areas of different laws in parts of the cosmos even now?
MsgId: *infinities(11)
Date: Sun Jul 27 21:23:05 EDT 1997
From: Lee_Smolin At: 128.118.49.137
No, the evidence from recent work in string theory is that there can only be transitions between the different phases at extreme events, when the density becomes enormous, basically only near black hole "singularities" where the densities grow quickly arbitrarily large.
MsgId: *infinities(12)
Date: Sun Jul 27 21:24:18 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
So what's the other reason?
MsgId: *infinities(13)
Date: Sun Jul 27 21:26:13 EDT 1997
From: Lee_Smolin At: 128.118.49.137
The other reason is the embaresment that the constants in the laws such as the masses of the particles seem to be finely tuned so as to allow a universe full of galaxies and stars, which also has biochemistry ... That is if the constants are increased or decreased reasonably small amounts it is often the case that they lead to a world without many different kinds of nuclei or atoms, or without supernovas. This is usually taken as evidence for some version of the anthropic principle, but i dont believe that is science. The combination of the two circumstances tells us that we must look for a real reason why a choice was made in a way that leads to a complex world with many kinds of atoms.
MsgId: *infinities(16)
Date: Sun Jul 27 21:30:51 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Before we get to why those choices were made in a way that produces the variegated cosmos we live in, I wonder how that choice would happen. What's the mechanism or process by which these conditions are set at one value or another? How many iterations would there be -- would the conditions be set once, or would there be a series of phase shifts?
MsgId: *infinities(17)
Date: Sun Jul 27 21:32:51 EDT 1997
From: Lee_Smolin At: 128.118.49.137
When I began thinking about these things my idea was to avoid these kinds of questions, to make the simplest, dumbest hypotheses about the changes, like that they would be random, and see if there were testable consequences. Now, a few years later there has been much progress in quantum gravity and string theory and we can just begin to sketch out real calculations about these phase changes. But nothing good enough has really been done yet. So the best answer is we don't know.
MsgId: *infinities(19)
Date: Sun Jul 27 21:36:09 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Could such a change happen suddenly, even now, so that it would wipe out the existing laws as we know them -- and possibly wipe out matter and life as we know them as well?
MsgId: *infinities(20)
Date: Sun Jul 27 21:37:55 EDT 1997
From: Lee_Smolin At: 128.118.49.137
No, because the densities and energies involved are way off scale of what happens -- even from the most energetic cosmic rays observed. So we are safe, no millenial fantasies here. The future will arrive.
MsgId: *infinities(21)
Date: Sun Jul 27 21:41:08 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Phew. Then let's get to the "why" part of the question -- how the idea that the cosmological laws are somehow evolved over time helps to explain why we've got a universe hospitable to life. Even if we accept the idea of mutable physical laws, what's the guiding principle of cosmological evolution? In natural selection there's "survival of the fittest" or some such governing demand that helps determine the path of development. Is cosmological evolution merely random, or is there some analogous force acting to select cosmic laws as well?
MsgId: *infinities(22)
Date: Sun Jul 27 21:44:00 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Natural selection is random, it is not a force. It is just the logic of frozen accident. To apply it to any context you need three things: some reproduction of a system, some variation in its properties, and a feedback where some of the properties determine how many copies of itself get made. As far as I know this is the only mechanism that can explain the otherwise improbable growth of variety and complexity. So the question is whether this logic can be applied to cosmology and physics.I know of several ways to try to do this. The one that holds up best so far against observation is the idea I describe in the book in which the reproduction is by black holes. I use the old idea, which goes back several decades, that rather than forming singularities where time ends...instead there is a """bounce""" where a new expansion of space begins, which expands to the future of the black hole, but cannot be seen outside of it. The variation is what we were discussing, the phase changes in the laws. The selection is then that universes with different laws...will produce different numbers of black holes. The bad things about this idea are obvious, but the good thing is that it is very testable, it is very easy to imagine it will be falsified by certain astronomical observations. In fact I would not be surprised if this happens. But if it is I would still expect a theory to be discovered that employed the logic of natural selection. I don't see any other way to resolve the puzzles we mentioned at the beginning.
MsgId: *infinities(28)
Date: Sun Jul 27 21:52:30 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
You mention (here and in your book) that many of the ideas you're working with have been around in some form for decades, if not centuries. Some of the basic logic goes back at least to Leibniz's objections to Newton's physics. Why do you think the concept of evolved cosmic laws hasn't been championed before? It does seem to provide a very elegant answer to the problem of the arbitrariness of so many factors in physical theories.(I've just opened the room for questions. We don't have much time left, but if you've got something you'd like to ask, please feel free to jump in.)
MsgId: *infinities(30)
Date: Sun Jul 27 21:55:39 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Yes, I know statements of the idea by Diderot and Pierce.. but what is different now I think is 2 things. First, the search for a unification has proceeded very well, but left us with this unexpected result of many phases. Second, it was possible to make the idea testable.
MsgId: *infinities(31)
Date: Sun Jul 27 21:56:55 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
What would you suggest as a way to test the idea, and is such a test feasible today?
MsgId: *infinities(32)
Date: Sun Jul 27 21:58:41 EDT 1997
From: Lee_Smolin At: 128.118.49.137
The observation of a 3 solar mass neutron star -- something that could happen at any moment -- would be very hard to square with the theory. The reasons require more astronomy than we have time for, its described in the book, but the main idea is that supernovas may leave neutron stars or black holes as remnants, and if very massive neutron stars are impossible all these become black holes.
MsgId: *infinities(34)
Date: Sun Jul 27 22:04:36 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
We're just about out of time, Lee, and obviously we've barely had time to scratch the surface of the ideas in your book. Let me ask this: You say you wouldn't be surprised if your theory were refuted by observation, but I must admit I have trouble thinking of another means (other than black holes) that would permit the sort of evolutionary cosmological scheme you describe. Even if your particular vision isn't verified, you think another evolutionary process will be found. Any idea what such an alternative evolutionary model might be based on, if not black holes, as in yours?
MsgId: *infinities(35)
Date: Sun Jul 27 22:07:04 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Yes, I have to go for dinner. One idea which disagrees with observation has the variation of the laws taking place all in our past, without black holes. this is described in my first paper on the subject, it can't be consistent with the accuracy that the cosmic background radiation is perfectly random. There are some other ideas I'm playing with now with some collaborators, including Stu Kauffman. But nothing really works well yet.
MsgId: *infinities(37)
Date: Sun Jul 27 22:09:46 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Well, then, I'm pulling for the black holes. The idea of our universe (and others like it) budding into millions and billions of others is just too great not to want it to be true. On that note, I guess we should call it a night, and let you get something to eat. Thanks for appearing here on Infinities, Lee. Perhaps we could have you back sometime to go into more detail -- I think your ideas are fascinating and I'd love to have a chance to get into a more involved discussion. At any rate, those whose interest has been piqued by this brief survey can find a fuller discussion in Lee's book, "THE LIFE OF THE COSMOS." For now, that's all for Infinities. Good night!
MsgId: *infinities(38)
Date: Sun Jul 27 22:11:02 EDT 1997
From: Lee_Smolin At: 128.118.49.137
Good night, thanks, this was fun, I was sorry only nobody out there contributed, oh well, thanks again, Lee
MsgId: *infinities(39)
Date: Sun Jul 27 22:12:13 EDT 1997
From: Rob_Killheffer At: 205.198.117.93
Perhaps if we do another we can get some others involved, now that we've got some of the basic ideas covered. It's hard with a complex topic like this. Thanks again!
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